Adapting A Vintage Engine to a Modern Transmission - Trans-Adaptation

To me, the appeal of vintage engines typically ends at the bellhousing surface—I basically have no use for the accompanying tranny. I know, there are plenty of you who are particular to Top Loaders and the like, and there’s absolutely nothing wrong with that. Unless you’re going drag racing or trying to keep up with 65-mph (plus!) traffic on a regular basis, early engines are just fine with early transmissions. Knowing their limitations helps the driver adapt to the particular conditions at hand, but why not do the opposite?

Adapting a vintage engine to a modern transmission is the solution I’ve come to live by. Whether it’s via a four-speed automatic overdrive, or as in this case, a five-speed manual, taking a brunt of the load off an old engine—as well as prolonging its life—ultimately takes some of the load off the driver, and in turn, the vehicle itself. I don’t know about you, but buzzing along at 3,000-plus rpm on the freeway and barely doing 55 isn’t time well spent behind the wheel, at least not for me. And in a solid front-axle car or truck with all-wheel drum brakes, winding out Third gear is just another downbeat driving factor I can do without. But, throw in an extra gear or two, and keeping up with traffic—and being able to hear yourself think—is no longer one of those negative aspects.

Since all of my recent Chevy inliners got the deserving drivetrain upgrade, I felt the 8BA Flathead going in the ’33 Tudor deserved the same. Weighing all of my options—automatic (C4 or Turbo 350) or manual (S-10/Camaro T-5 or Tremec TKO)—I ultimately decided to “stick” with what I knew best: a TKO 500 five-speed. But the decision making didn’t end there, and as it would turn out, my next one was by far the most difficult choice to make.

2/25Wilcap, maker of all things that make adapting modern technology to our antiquated engines, manufactures quite the variety of Flathead tranny adapters (left and center); while newcomer QuickTime (right) offers two direct fit adapters for Ford-only applications (no GM/Muncie patterns currently offered).

Upon engaging discussions with my contacts at Tremec, I was ultimately faced with deciding on a particular gear ratio for the TKO 500 I was ordering. Sounds easy enough, right? Well, I thought so myself at first … but I would end up changing my mind, oh, at least three times before coming to a “final” decision. You see, there’s a lot more to manual overdrives than just the addition of a Fifth—or even a Sixth—gear. Not only do you have a choice in how much overdrive you get (0.64, 0.68, or 0.82), you have the option of how much “off-the-line” gear (First), as well. For instance, both the 0.64 and 0.82 overdrives have a 2.87 First, while the 0.68 has a stout 3.27 First. Now if you’re thinking it’s all just a matter of picking the right combo simply based on the transmission data, think again—we’ve still got to factor in a few more very important variables … engine, rearend gear, and rear tire diameter. In my case that equated to a low-revving 8BA Flathead, a Winters 3.86 ring-and-pinion, and a 31.5-inch Coker/Excelsior bias-ply. After quite a few back-and-forth email and phone sessions with my “patient” friends at Tremec, the final-final decision was made to go with the 0.82 TKO 500. With that gear setup, at 76 mph I’d be turning 2,500 rpm (both the 0.64/0.68 ODs would require speeds in excess of 90 mph to attain the same rpm—way too tall for my little Flatty).

But I still had one last component to fill in the blank between the five-speed and the Flathead: the adapter. Thanks to Patrick McGuire, owner/proprietor of Wilcap Engineering, that blank was more than filled. McGuire was gracious enough to send me everything he has and/or makes to mate late-model transmissions with all Flathead models. Whether it’s a Turbo 350 or a Muncie, his products are manufactured to exact tolerances, meaning you won’t have to do any jimmy-rigging or head-scratching (he also supplies very descriptive instructions with each kit).

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So, if you’re tired of winding out that ol’ Flathead of yours just to keep pace with grandma on the freeway, consider a little modern trans-adaptation. I highly recommend it!